Endoscopic snare device

ABSTRACT

The present subject matter discloses a tissue removal tool for use with an endoscope. The tool comprises a loop formed by a piece of wire and movable between an open position and a closed position, and a transmitting assembly comprising: a handle; and a link having a first end attached to the handle and a second end attached to the loop, the loop portion being movable between the open and closed position by action of the handle. The loop is defined in the open position by a proximal portion and a distal portion. The widest portion of the loop is more proximal to a proximal end of the loop than the mid-point of the length of the loop is.

CROSS-REFERENCES

This application is a continuation of U.S. patent application Ser. No. 15/866,401, filed Jan. 9, 2018, which claims the benefit of U.S. Provisional Patent Application No. 62/444,144, filed on Jan. 9, 2017, both disclosures of which are hereby incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present subject matter relates generally to endoscopic snare devices.

BACKGROUND

Polypectomy, or the removal of polyps, has become one of the most common endoscopic procedures in gastrointestinal endoscopy today. Its relative simplicity often belies the effectiveness of the procedure at preventing colorectal cancer. The National Polyp Study (NPS) demonstrated a reduction in the incidence of colorectal cancer of 76%-90% following colonoscopic polypectomy. Standard practice for polypectomy has been to use an electrocautery or “hot” snare to remove polyps due to the fact that it reduces the risk of bleeding as a result of the coagulation effect created by the current. Electrocautery, however, can create inadvertent damage to healthy tissue and may not be necessary for smaller sized polyps where bleeding risk is not a concern.

A “cold” snare, such as US Endoscopy Group Inc.'s Exacto® snare, is designed for polypectomy procedures where diminutive polyps are encountered. It enables a clean cut that reduces polyp “fly away” form the resection site. Studies comparing Exacto® snare to hot snares have shown that, for diminutive polyps in the 3-8 mm range, there is no difference in postpolypectomy bleeding and it requires less time to use than hot snares while being just as safe and effective.

SUMMARY

The present subject matter describes a tissue removal tool for use with an endoscope. The tool comprises a loop formed by a piece of wire and movable between an open position and a closed position, and a transmitting assembly comprising: a handle; and a link having a first end attached to the handle and a second end attached to the loop, the loop portion being movable between the open and closed position by action of the handle. The loop is defined in the open position by a proximal portion and a distal portion. The widest portion of the loop is more proximal to a proximal end of the loop than the mid-point of the length of the loop is.

The present subject matter further describes a tissue removal tool having a cutting section disposed along the distal portion of the loop.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the general inventive concepts will become apparent from the following detailed description made with reference to the accompanying drawings.

FIG. 1 is a perspective view of a retrieval device, showing a snare in an open position;

FIG. 2 is an enlarged sectional view of a portion of the retrieval device of FIG. 1, showing the snare in a closed position within a conduit;

FIG. 3 is an embodiment of the loop with a general cable form design;

FIG. 4 is an embodiment of the loop with a general monofilament form design;

FIG. 5 is a first embodiment of the loop with a distal cutting section and a proximal portion formed from separate wires;

FIGS. 6a-6b show a second embodiment of the loop with microtomes or cutting elements;

FIG. 7 is a third embodiment of the loop with a torsion tip; and

FIGS. 8a-8c show a fourth embodiment of the loop with separate loop elements;

FIGS. 9a-9b show a fifth embodiment of the loop with a tapered or ground portion;

FIG. 10 is a sixth embodiment of the loop with a coined proximal portion;

FIG. 11 is a seventh embodiment of the loop with a coined or non-coined proximal portion and a coined distal portion;

FIGS. 12a-12b show an eighth embodiment of the loop with a plurality of coined sections;

FIG. 13 is a ninth embodiment of the loop showing a method for mounting cutting elements; and

FIG. 14 is another embodiment of the loop detailing the loop.

DETAILED DESCRIPTION OF INVENTION

This Detailed Description merely describes exemplary embodiments in accordance with the general inventive concepts and is not intended to limit the scope of the invention or the claims in any way. Indeed, the invention as described by the claims is broader than and unlimited by the exemplary embodiments set forth herein, and the terms used in the claims have their full ordinary meaning.

The general inventive concepts will now be described with occasional reference to the exemplary embodiments of the invention. This general inventive concept may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the general inventive concepts to those skilled in the art.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art encompassing the general inventive concepts. The terminology set forth in this detailed description is for describing particular embodiments only and is not intended to be limiting of the general inventive concepts. As used in this detailed description and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

Unless otherwise indicated, all numbers such as, for example, numbers expressing measurements or physical characteristics, used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless otherwise indicated, the numerical properties set forth in the specification and claims are approximations that may vary depending on the suitable properties sought to be obtained in embodiments of the invention. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the general inventive concepts are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical values, however, inherently contain certain errors necessarily resulting from error found in their respective measurements.

The present application describes a tissue removal tool for use with an endoscope, comprising: a loop formed by a piece of wire and movable between an open position and a closed position; a handle; and a link having a first end attached to the handle and a second end attached to the loop, the loop being movable between the open and closed position by action of the handle, wherein the loop is defined in the open position by a proximal portion and a distal portion.

Referring to FIG. 1, the exemplary tool 10 includes a loop 12 formed by a piece of wire 14. A wire of any suitable material may be used to form the loop, such as for example, a metal, such as stainless steel, nitinol, plastic or carbon nanotube, glass fiber, or hybrid technology. The loop may also be formed by a monofilament or a cable. The variations in the wire shape and orientation along the length of the wire may be made by mechanically bending or twisting a preformed wire into the desired shape and orientation, or the wire may be originally manufactured to have the desired shape and orientation, such as for example, a preformed plastic piece. A suitable material will be flexible and have memory to allow deployment and retrieval of the loop. The wire forms a plurality of segments separated by collapse-resistant bends to define a loop opening. The loop is movable between an open position, or deployed position, and a closed position, or retrieved position. The loop 12 is illustrated in an open position in FIG. 1. The loop is polygon-shaped and, specifically, the loop is generally diamond-shaped. In FIG. 2, the loop 12 is shown in a closed position within a distal portion of the tool 10. As discussed herein, the loop 12 is within a conduit 18. In this closed or retrieved position, the exemplary loop has a length L₁.

The tool may include a support assembly and a transmitting system for moving the loop between an open position and a closed position. In the exemplary tool 10 illustrated in FIG. 1, the support assembly includes a base or body 16 and an elongated hollow tube, tubular member or conduit 18. The transmitting assembly includes a handle 20 movable relative to the body 16 and a link 22. One end of the link is fixed to the handle and a second end is remote from the body. As shown in FIGS. 1 and 2, the link 22 extends substantially through a length of the conduit 18. The conduit 18 may be any suitable, small-diameter tube formed of a low-friction flexible material such as, for example, polytetrafluorethylene, high density polyethylene, polyether block amide, or other comparable materials. The conduit 18 defines a lumen with an opening at a distal second end 28, as best seen in FIG. 2 which shows a cross-sectional view of a distal portion of the tool 10. A proximal first end 30 of the conduit is fixed to the body 16.

The handle allows an operator to move the loop back and forth between a deployed position, as shown in FIG. 1, and a closed position, as shown in FIG. 2. Referring again to FIG. 1, the body 16 includes a fixed ring 24 at a proximal end. The handle 20 may be slid by an operator relative to the body 16 by use of the handle 20 and, specifically, by use of one or both of two rings 26 a, 26 b. The handle 20 is mounted over an elongated section of the body 16 and is movable relative to the body in the direction D₁ to deploy the loop 12, or in an opposing direction D₂ to close the loop 12. For example, an operator may place a finger in each of the rings 26 a, 26 b and a thumb of the same hand in the body ring 24. By moving the two fingers in the direction D₁, an operator can move the handle 20 relative to the body 16. This movement of the handle will deploy the loop. In contrast, the handle 20 can be slid in the opposite direction D₂ by pulling one's fingers towards one's thumb to close the loop.

A link 22 is connected to the handle 20 for transferring axial motion from the handle 20 to other parts of the device. The link may be constructed of any suitable rigid material, and may be solid, hollow, or any suitable elongated object or combination of objects. The link may be one piece or formed from a series of pieces and connections, such as for example, hypodermic tubes, swage connections, and cables. The link 22 has a first end fixed to the handle 20 and a second end remote from the body 16. As shown in the drawings, the link extends substantially through the conduit 18.

FIG. 3 shows a general form for a cable cold cutting snare loop. FIG. 4 shows a general form for a monofilament cold cutting snare loop. The loops 12 comprise a distal portion 120 and a proximal portion 130. The loop comprises a cutting section 140 along the distal portion 120 of the loop 12. The cutting section 140 covers roughly ⅓ to ½ of the loop 12, and may be continuous or discrete. In some embodiments, the cutting section 140 extends about 1-5 mm out from the distal end 150 in either direction. In some embodiments, the cutting section 140 extends about 5 mm to 15 mm out from the distal end 150 in either direction. In some embodiments, the cutting section 140 extends about 10 mm out from the distal end 150 in both directions. In some embodiments, the cutting section 140 extends about 5 mm to 15 mm out from the distal end 150 in both directions. The cutting section 140 needs to be thin enough to provide cutting pressure to tissue. The cutting section 140 comprises a diameter of 0.36 mm or thinner so as to enable cold cutting of tissue. In some embodiments, the diameter is 0.30 or thinner. The cutting mostly occurs on the distal portion 120 of the snare by virtue of tensile mechanics of the snare as it is retracted into the tubular member 18. The distal tip 150 may also be optimized to dissipate stress uniformly so as not to deform during retraction.

The proximal portion 130 of the loop 12 generally does not perform cutting but provides assistance and support to encircle and recruit tissue for cutting. Increasing the stiffness of the proximal portion allows for greater indentation of the tissue which improves tissue recruitment. The stiffer proximal portion 130 can be about the proximal ⅓ to ½ of the loop 12. The proximal portion may vary in stiffness along its length.

In an embodiment shown as FIG. 5, the proximal portion 130 comprises flat wire or coined cable. The cutting section 140 generally comprises thinner wire than the proximal portion 130. These separate portions may be joined together by welding, gluing, crimping, swaging, soldering, or other techniques familiar to those skilled in the art.

In an embodiment shown as FIGS. 6a and 6b , the cutting section 140 comprises cutting blades disposed on an otherwise non-cutting snare wire.

In an embodiment shown as FIG. 7, the loop 12 is a solid rectangular wire filament loop with a torsion tip 150 to preserve its shape.

In some embodiments, such as those shown as FIGS. 8a-8c , the loop 12 comprises an inner loop 170 (i.e., cutting section) and an outer loop 160. The inner loop 170 is bonded (i.e., welded or other known suitable bonding methods) to the outside loop 160 in at least one location. The inner loop 170 comprises a thinner wire that is configured to be more effective for cold cutting. The outer loop 160 is thicker and stiffer than the inner loop 170. The outer loop 160 allows the loop 12 to indent and recruit tissue. In some embodiments, the inner loop 170 only covers the distal/mid portion of the loop 12, since that is where the cutting truly occurs. In some embodiments, the inner loop 170 is a full loop, since this may make fixturing/manufacture more efficient. In some embodiments, the inner loop 170 has a round cross-section. In some embodiments, the inner loop 170 is a flat or square wire.

In an embodiment shown in FIGS. 9a and 9b , the loop 12 comprises tapered or ground wire. The proximal portion 130 is thicker than the distal portion 120. The tool may further comprise mechanisms for promoting positioning of the loop 12 within the body, such as a rotatable link 22. In some embodiments, the link 22 is of sufficiently less torsional rigidity than the legs of the loop 12.

In an embodiment shown in FIG. 10, the loop 12 comprises cable or monofilament loop with a coined proximal portion 130 and non-coined distal portion 120.

In an embodiment shown in FIG. 11, the loop 12 comprises a cable or monofilament loop with a coined distal portion 120, which creates a sharp inner edge to provide for cutting action. In some embodiments, the proximal portion may also be coined in a perpendicular plane to the distal coined portion.

In some embodiments shown in FIGS. 12a and 12b , the loop 12 comprises coined at various locations 180 so as to be advantageous for cutting or grasping tissue. It may be several small level and cross-sectional changes, a few longer sections and may be either symmetrical or asymmetrical with respect to the loop centerlines (vertical and horizontal).

In an embodiment shown in FIG. 13, the cutting section comprises a cutting element 190 with eyelets 200. The eyelets 200 could have the wire slid through and then crimped, welded, glued or otherwise bonded in place. The eyelets 200 could be any opening shape, such as round or square.

Referring now to FIG. 4, in the exemplary loop 12, the wire is bent at the distal tip 150 to form a torsion tip, or a nearly 360° circular tip. The tip allows for dissipation of stress through the snare, something that is of particular importance when cold snaring because of the relatively larger forces used compared to hot snaring. One feature to help to facilitate this is to use multifilament cable. The strands in the cable move relative to one another and allow for stresses to be more evenly spread across the snare body. To achieve the same effect in monofilament wire, one can create a loop that mimics a standard torsion spring without increasing the cutting thickness of the tip. Because the tip is a loop and not a simple bend, stress is distributed more evenly around the entire circumference upon closing, minimizing plastic deformation.

The distal tip 150 of the tool may have alternative shapes. US 2014/0052142 A1 and US2015/0066045 A1 disclose multiple distal loop or coil tip designs, the contents of which are incorporated herein. The wire may form a torsion tip with a 180° bend. In another distal tip, the wire within the 180° bend may be in a landscape orientation. In another exemplary distal tip, the loop is formed by a wire having two portions. The two wire portions form an atraumatic tip at a distal most point. As assembled, the wire portions function as a loop in the same way as discussed herein.

Another aspect of the present subject matter is to provide a new shape of the loop. Referring to FIG. 14, in some embodiments, the loop 152 comprises a widest portion 166 and a length L measured between a proximal end and a distal end. The proximal end is defined where the loop begins to close during retraction into the tubular member, irrespective of where the loop connection physically may occur. The distal end is defined by the most distal end, or ends, of the loop 152. In any instance where there are proximal legs that are excessively long, and/or the distal tip is inverted or of any other unusual geometry, the midpoint shall be considered only with respect to the broad portions of the form, which is defined between the proximal end and the distal end(s). The widest portion 166 of the loop 152 is more proximal to the tubular member 18 than the mid-point of the length L of the loop 152 is. In other words, the widest portion 166 is closer to the tubular member 18 than the mid-point of the length L of the loop 152, such that the loop 152 is easier to be controlled during the procedures. In some embodiments, the distance D from the mid-point of the length L of the loop 152 to the widest portion 166 of the loop 152 is about 3%-45% of the length L. In some embodiments, the distance D from the mid-point of the length L of the loop 152 to the widest portion 166 of the loop 152 is about 10%-35% of the length L. In some embodiments, the distance D from the mid-point of the length L of the loop 152 to the widest portion 166 of the loop 152 is about 12%-25% of the length L.

It should be understood that some or all of the features described above may be applied to any suitable endoscopic devices or combination of endoscopic devices, such as snare-needle device, a multistage snare, or an endoscopic retrieval device.

A person skilled in the art should understand that although the above-described snare features are designed for cold cutting, they may also be utilized with electrocautery without compromising the features that make them useful for gathering and cutting tissue.

A person skilled in the art should understand that the endoscopic device described in the present subject matter is not necessary to comprise the support assembly (including the base and the elongated tubular member) and/or the transmitting assembly (including the handle and the link). A handle may be formed by or connected to the proximal end of the loop.

While various inventive aspects, concepts and features of the general inventive concepts are described and illustrated herein in the context of various exemplary embodiments, these various aspects, concepts and features may be used in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein all such combinations and sub-combinations are intended to be within the scope of the general inventive concepts. Still further, while various alternative embodiments as to the various aspects, concepts and features of the inventions (such as alternative materials, structures, configurations, methods, circuits, devices and components, alternatives as to form, fit and function, and so on) may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed. Those skilled in the art may readily adopt one or more of the inventive aspects, concepts or features into additional embodiments and uses within the scope of the general inventive concepts even if such embodiments are not expressly disclosed herein. Additionally, even though some features, concepts or aspects of the inventions may be described herein as being a preferred arrangement or method, such description is not intended to suggest that such feature is required or necessary unless expressly so stated. Still further, exemplary or representative values and ranges may be included to assist in understanding the present disclosure; however, such values and ranges are not to be construed in a limiting sense and are intended to be critical values or ranges only if so expressly stated. Moreover, while various aspects, features and concepts may be expressly identified herein as being inventive or forming part of an invention, such identification is not intended to be exclusive, but rather there may be inventive aspects, concepts and features that are fully described herein without being expressly identified as such or as part of a specific invention. Descriptions of exemplary methods or processes are not limited to inclusion of all steps as being required in all cases, nor is the order that the steps are presented to be construed as required or necessary unless expressly so stated. 

We claim:
 1. A tissue removal tool for use with an endoscope, comprising: a loop formed by a piece of wire and movable between an open position and a closed position, and a transmitting assembly comprising: a handle; and a link having a first end attached to the handle and a second end attached to the loop, the loop portion being movable between the open and closed position by action of the handle; wherein the loop is defined in the open position by a proximal portion and a distal portion, and wherein a widest portion of the loop is more proximal to a proximal end of the loop than a mid-point of the length of the loop is.
 2. The tissue removal tool of claim 1, wherein a distance from the mid-point of the length of the loop to the widest portion of the loop is about 3%-45% of the length.
 3. The tissue removal tool of claim 2, wherein a distance from the mid-point of the length of the loop to the widest portion of the loop is about 10%-35% of the length.
 4. The tissue removal tool of claim 3, wherein the distance from the mid-point of the length of the loop to the widest portion of the loop is about 12%-25% of the length.
 5. The tissue removal tool of claim 1 further comprising: a support assembly comprising a base and an elongated tubular member, wherein the handle is movable relative to the base, and the link extends through at least a portion of the tubular member.
 6. The tissue removal tool of claim 5 further comprising: a cutting section disposed at least at the distal portion of the loop.
 7. The tissue removal tool of claim 6, wherein the cutting section covers about ⅓ to ½ of the loop at the distal portion of the loop.
 8. The tissue removal tool of claim 6, wherein the cutting section extends about 5 mm to 15 mm from a distal end of the loop in either direction.
 9. The tissue removal tool of claim 8, wherein the cutting section extends about 10 mm from a distal end of the loop in either direction.
 10. The tissue removal tool of claim 6, wherein the cutting section comprises a diameter of 0.36 mm or thinner.
 11. The tissue removal tool of claim 6, wherein the proximal portion of the loop comprises flat wire or coined cable, and the cutting section comprises thinner wire than the proximal portion.
 12. The tissue removal tool of claim 6, wherein the cutting section is a cutting element comprising cutting blades disposed on an otherwise non-cutting snare wire.
 13. The tissue removal tool of claim 6, wherein the loop comprises an inner loop and an outer loop, wherein the inner loop is secured to the outer loop in at least one location, and the inner loop is thinner than the outer loop.
 14. The tissue removal tool of claim 13, wherein the inner loop only covers the distal portion of the loop.
 15. The tissue removal tool of claim 13, wherein the inner loop substantially covers the whole loop.
 16. The tissue removal tool of claim 6, wherein the loop comprises tapered or ground wire, and the proximal portion is thicker than the distal portion.
 17. The tissue removal tool of claim 6, wherein the loop comprises a cable or a monofilament snare with a coined proximal portion and a non-coined distal portion.
 18. The tissue removal tool of claim 6, wherein the loop is coined at various locations.
 19. The tissue removal tool of claim 6, wherein the cutting section is a cutting element with eyelets, wherein the eyelets are configured to have the wire slid through.
 20. The tissue removal tool of claim 5, wherein the loop is a solid rectangular wire filament loop with a torsion tip. 